netty5/resolver-dns/src/main/java/io/netty/resolver/dns/DnsCache.java
Stephane Landelle b4be040f30 Introduce DnsCache API + DnsResolver extensibility
Motivation:
Caching is currently nested in DnsResolver.
It should also be possible to extend DnsResolver to ba able to pass a different cache on each resolution attemp.

Modifications:

* Introduce DnsCache, NoopDnsCache and DefaultDnsCache. The latter contains all the current caching logic that was extracted.
* Introduce protected versions of doResolve and doResolveAll that can be used as extension points to build resolvers that bypass the main cache and use a different one on each resolution.

Result:

Isolated caching logic. Better extensibility.
2016-01-08 14:46:47 +01:00

69 lines
2.1 KiB
Java

/*
* Copyright 2016 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.resolver.dns;
import io.netty.channel.EventLoop;
import java.net.InetAddress;
import java.util.List;
/**
* A cache for DNS resolution entries.
*/
public interface DnsCache {
/**
* Clears all the resolved addresses cached by this resolver.
*
* @return {@code this}
*
* @see #clear(String)
*/
void clear();
/**
* Clears the resolved addresses of the specified host name from the cache of this resolver.
*
* @return {@code true} if and only if there was an entry for the specified host name in the cache and
* it has been removed by this method
*/
boolean clear(String hostname);
/**
* Return the cached entries for the given hostname.
* @param hostname the hostname
* @return the cached entries
*/
List<DnsCacheEntry> get(String hostname);
/**
* Cache a resolved address for a given hostname.
* @param hostname the hostname
* @param address the resolved adresse
* @param originalTtl the TLL as returned by the DNS server
* @param loop the {@link EventLoop} used to register the TTL timeout
*/
void cache(String hostname, InetAddress address, long originalTtl, EventLoop loop);
/**
* Cache the resolution failure for a given hostname.
* @param hostname the hostname
* @param cause the resolution failure
* @param loop the {@link EventLoop} used to register the TTL timeout
*/
void cache(String hostname, Throwable cause, EventLoop loop);
}